Bayesian thinking for toddler & Bayesian probabilities for babies [book reviews]

My friend E.-J.  Wagenmakers sent me a copy of Bayesian Thinking for Toddlers, “a must-have for any toddler with even a passing interest in Ockham’s razor and the prequential principle.” E.-J. wrote the story and Viktor Beekman (of thesis’ cover fame!) drew the illustrations. The book can be read for free on https://psyarxiv.com/w5vbp/, but not purchased as publishers were not interested and self-publishing was not available at a high enough quality level. Hence, in the end, 200 copies were made as JASP material, with me being the happy owner of one of these. The story follows two young girls competing for dinosaur expertise, and being rewarded by cookies, in proportion to the probability of providing the correct answer to two dinosaur questions. Toddlers may get less enthusiastic than grown-ups about the message, but they will love the drawings (and the questions if they are into dinosaurs).

This reminded me of the Bayesian probabilities for babies book, by Chris Ferrie, which details the computation of the probability that a cookie contains candy when the first bite holds none. It is more genuinely intended for young kids, in shape and design, as can be checked on a YouTube video, with an hypothetical population of cookies (with and without candy) being the proxy for the prior distribution. I hope no baby will be traumatised from being exposed too early to the notions of prior and posterior. Only data can tell, twenty years from now, if the book induced a spike or a collapse in the proportion of Bayesian statisticians!

[Disclaimer about potential self-plagiarism: this post or an edited version will potentially appear in my Books Review section in CHANCE.

conditional confusion [X validated]

continuously tough [screenshots]

As I was looking to a pointer on continuous random variables for an X validated question, I came across those two “definitions”…

stuck exchange

Made an attempt at explaining on X validated why simulating from the joint was equivalent to simulating from the marginal then from the conditional. Unfortunately failed as I could not fathom where the OP’s difficulty was. It seems it started at defining what drawing from a distribution meant… Then someone came by asking why I was writing the exponential in this unusual way (this was a barred E for expectation) and whether or not the “thin hollow rectangle” (a barred I for indicator) was standing for identity, that is

Reaching a point of incomprehension from which I could not recover…

Amy in Randomland [book review]

Amy’s Luck is a short book by David Hand that I recently received for review in CHANCE. David, whom I have known for quite a while now, is professor at Imperial College London. This is not his first book, by far! But this may be the most unusual one, if not the shortest. Written as a pastiche of Alice’s Adventures in Wonderland, it tells of the adventures of a young girl named Amy in the pursuit of luck or at least of its meaning. It has about the same number of chapters as Carroll’s book and could easily be read on a leisurely boat trip from Oxford to Godstow. While non-sensical and playing on the imprecision of the English language, its probabilist is both correct and rational. References to the original Alice abound and I presumably missed a fair portion of them, having read Alice (in French) decades ago. The book also contains illustrations from the author, gathered into a charm bracelet printed on the cover and a most helpful appendix where David points out the real world stories behind those of Amy, which is also full of gems, like Kolmogorov being a train conductor in his youth. (Missing an addition about Galton’s quincunx, esp. when his cousin Darwin is more than mentioned.) Or Asimov creating the milihelen to measure how much beauty was required to launch a ship. Overall, it is quite charming and definitely enjoyable, if presumably not accessible by the same audience as Alice‘s. And unlikely to take over Alice‘s! But from “She could understand the idea that coins had heads”, to a Nightingale rose renamed after Miss Starling, to the permutation of Brown, Stein, and Bachelier into Braun, Stone, and a bachelor, David must have had fun writing it. As others will while reading it and trying to separate probabilistic sense from non-sense.

[Disclaimer about potential self-plagiarism: this post or an edited version will eventually appear in my Book Review section in CHANCE.]